Slvrthp, the Amalgam

Whenever another sliver enters the battlefield under your control, if it's white, slivers you control gain your choice of vigilance or lifelink for the rest of the game. The same is true for a blue sliver and flying or hexproof, a black sliver and deathtouch or menace, a red sliver and haste or first strike, and a green sliver and trample or reach.
Everyone is lost until they find thems